The present invention relates to imidazoline derivatives which are novel compounds, a process for preparing them, and a herbicide and a plant growth regulator containing them as an active component.
As disclosed in Japanese Patent Application Laid-Open No. 64637/1979, it is known that imidazolinone derivatives represented by the following general formula have herbicidal activity. ##STR2##
However, the herbicidal activity of the above compounds is not sufficiently high and furthermore the compounds are considered to have problems in that their residual period in the soil is relatively long, they would cause phytotoxicity on succeeding crop or would cause environmental pollution under bad conditions.
In view of the above problems, the present inventors made extensive investigations to develop a herbicide which exhibits high herbicidal activity even when used in a small dose and which has decreased environmental pollution and phytotoxicity on succeeding crop which occurs with persistence in the soil. The compounds also exhibit activity as a plant growth regulator.
In many cases, the herbicidal activity of a chemical substance markedly varies with slight modifications of the structure thereof, specifically in respect of e.g., the type, number and position of groups. Therefore it is difficult to estimate the herbicidal activity of a new compound merely from its similarity in chemical structure to the other compound.
As a result of extensive investigations, it has been found that specified imidazoline derivatives prepared by converting the cyclic structure portion of the benzene ring of the above known imidazoline derivatives into the non-cyclic structure has high herbicidal activity and a high plant growth regulating effect.